A wafer is a thin slice of semiconductor material often containing a plurality of microdevices, or dies. Dies are fabricated on the wafer, which is suspended within a supporting frame via mounting tape. A sawing or dicing process is performed on the wafer to separate the individual dies from each other. The mounting tape continues to hold the dies after the dicing process until the separated dies are removed from the mounting tape. Once fully removed, the dies are packaged and put into end-user electronic devices, usually as integrated circuits to provide electronic functionality to the devices.
The wafer surface is designed so that the individual dies are separated by a plurality of scribe lanes. A physical cutting tool such as a saw uses the scribe lanes as a cutting line during the separation process. The widths of the scribe lanes can vary depending on the width of the saw blade, but the scribe lines are at least wide enough to allow for the width of the saw blade. The scribe lane width is typically much smaller than the width of the individual dies. As such, the scribe lanes occupy a small portion of the wafer's surface area. Further, there can be multiple scribe lanes between adjacent die depending on the number of sacrificial electrical test modules required for verification of wafer conformance to electrical specifications prior to the die separation process.
A problem exists in known wafer dicing methods, however, when chipping or cracking of the die edge occurs during the dicing cut, particularly when dicing through brittle, low-k dielectrics. Although most dies incorporate die seals that help protect the edges of the dies, the dies are still highly susceptible to collateral damage from the dicing operation. In particular, cracks resulting from the dicing process can propagate significant distances from the saw line, and moisture from water exposure or intentional acceleration resulting from exposing packages to humid environments can lead to massive cracks in the scribe lanes that can migrate towards the die seal. In certain cases, such a crack can rupture the die seal and curtail the lifetime of the die.